Method and apparatus for finishing insulators



Sept. 6 1927.

A. E, KAUFFMAN METHOD AND APPARATUS FOR FINISHING INSULA'XORS Filed Feb. 9. 1926 Tin-1.2.

Ill VEN TOR I Arronnb Patented Sept. 6, 19.27.

UNITEDFSTATE'S ABRAM EDWARD' KAUFFMAN, OF EAST LIVERPOOL, OHIO, ASSIGNOR ,TO THE 11,. THOMAS & SONS COMPANY, OF EAST LIVERPOOL, OHIO, A CORPORATION OF OHIO.

METHOD D ArrAnA'r s roarmrsnme rursuna'roas.

Application fiI edlFebruaryS, 1926. Serial No. 87,067.

My invention relates to an improved method and apparatus for finishing insulators, and particularly to insulators of the pin type. The object of my invention is to apply to a pre-shaped insulator, while still in plastic condition, afinishing operation which (1) prevents or minimizes distortion of the insulator during its subsequent drying; (2) works or sizes the surface of the insulator and thus creates a surface condition which greatly reduces or entirely avoids the danger of crack formation on subsequent drying; and (3) imparts an exact and substantially permanent shape which is retained by the insulator during the subsequent steps ,of its manufacture. 1

In the accompanying drawings Fig. 1 is a plan view'of a tool for carry: ing out my finishing method;

Fig. 2 is a side elevation of the tool, and

Fig. 3 is a partial side elevation of the tool applied to the insulator. i

As explained in the prior patent to Buckley No. 1,465,157, it, has heretofore been sug- 5 gested to impart 'a' preliminary general shape to a plastic insulator blank by molding, and while still in plastic condition the blank has then been mountedupon a. rotary spindle and a cutting tool has been used to accurately cut a peripheral groove in the head area of the insulator for the'reception of a tie wire or the like. While an insulator formed in this fashion is accurately shaped when the cutter hasfinished its operation, I have found that the fiange'forming the upper wall of the groove hasa tendencyto sag and the groove become distorted during the subsequent drying. Moreover, there is a tendency to crack atth'e groove during the drying period, and the insulator is thus rendered defective. These difficulties result in a considerable wastage ofboth material and labor, thus enhancing cost of ture. v p

I have found that these troubles are practically eliminated if the blank, while still in plastic condition, is subjected to a finishing operation, such as hereinafter described.

According to w my invention, the blank is shaped to substantially its final form by a cutting tool which may be analogous to, that disclosed in the Buckley patent above mentioned, but with the difference that the final contour of the groove and flange, while approached, is not fully attained. I then apnianufacply a finishing roller which is pressed against the blank while the latter is rotated. This roller kneads or works the surface of the blank, compacting the clay-and imparting a smooth finish thereto, and at the same time gives the blank its desired final contour. The action of this finishing roller is thus quite different from that of the Buckley cutter, to which it issupplementary, and produces a finished article which is compacted a'ndsolidified at those'areas at which 'there is'danger of distortion; possesses'surface characteristics which minimize or prevent the forma'tionof cracks therein; and at the same time is accurately gauged to final shape.- I 5 I Y The apparatus employed for this purpose may conveniently resemble, in many respects, the Buckley apparatus. Thus, it"

comprises a. cap 15 shaped to fit upon and revolves with the head 16 of the insulator. Carried thereby, but swiveling with relation to the cap 15 is a hand grip 17 by means of which'the cap 15 may be readily applied to the head of the insulator.- A supporting arm 18 is pivoted on the stem of the hand grip 17, and a second arm 19 is pivoted at 20 to the arm 18. Detachably connected to the arm 19, and extending below the latter, is a hanger 21 which carries the grooving 'roll 22 i I which idles on the axis 23. A stop lug 24; projects from the arm 19 and bears against the margin of the arm 18 to limit the approach of the roller 22 toward the insulator.

The periphery of the roller 22 is shaped to the desired finished contour of the groove 25 formed adjacent the head 16 of the insulator 26.

The operation is as follows. Following the operation of a cutter, such as that of the Buckley patent above mentioned, the cap 15 of the present finishing tool is applied to the rotating insulatoir'26,'and thus accurately positions the tool upon the insulator. The arm 19 is then swung inward toward the insulator and the roller 22 enters the partially formed groove 25 into which it is pressed until the stop 24 is halted by'its engagement with the arm 18. During its inward movement, after engaging the clay at the groove 25,'the roller 22 knea-ds or compacts the clay at the surfaces engaged thereby, and its rolling frictional contact therewith produces a smooth, firm surface, which is resistant to cracking. Moreover,

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it will be noted that the skirt of the cap 15 closely approaches, or substantially coincides with, the upper face of the roller 22; thus the material displaced upward by the roller is confined by the cap 15, so that the cap and roller co-act to densely compact the flange :27 forming the upper Wall of :he groove 25. This kneading and L'Oll'n pacting of the clay in the flange Q? renders the latter structurally strong, with the result that during the subsequent drying operation there is no tendency of this flange to sag and deform the groove. The limit stop 2% gauges the depth of the groove 25, so that the latter is exactly formed to the desired depth. After the blank has been thus treated it isdried and glazed and baked in the usual fashion.

The detachability ot the roller-carrying hanger 21 from the arm 19 makes it possible to substitute rollers 01 diil'crent shape and contour, as may be desired for different types of insulators. The precise peripheral outline oi the roller may be varied, as also the shape of the cap 15. It is also obvious that the particular shape or type of insulator may be varied, since the advantages oil my process are not restricted to any particular insulator outline. The thought which underlies my invention is embodied in the treatment of any insulator while in plastic condition, to which approximately final shape has been imparted, so long as the operation thereon comprises applying to the plastic blank a finishing roller which hncads the clay into its final shape, coinpacts it at the surface, and simultaneously imparts a smooth surface finish thereto. lVith this understanding I claim as my invention- 1. A finishing tool for plastic insulator blanks, comprising a cap adapted to be applied to an insulator head, and an associated swinging idler roll adapted to be pressed against the side of the blank adjacent the cap, and to coact with the latter in co1npact ing and shaping the material of the blank in the neighborhood of the cap.

2. The method 01' forming a ceramic insulator which comprises molding plastic ceramic material to the general contour of the insulator, cutting to shape a groove in the neck of the insulator blank, and Working the grooved area to compact, smooth and shape the latter to finished contour.

S. The method of torminga ceramic insulator which comprise shaping plastic ceramic material to the general contour of the insulator provided with a neck groove, and Working the material in the grooved area against restraining pressure applied to the insulator top, whereby the material in the area of the groove is compacted, smoothed and shaped to finished contour.

In testimony whereof I have signed my name to this specification.

AER-AM EDlVARD KAUFFMAN. 

